Cardiovascular disease (CVD) contributes substantially to the overall morbidity of HIV-infected individuals. Factors that epidemiologically and prospectively are the strongest predictors of .atherosclerosis are dyslipidemia and impairmen of intracellular cholesterol metabolism. Dyslipidemia in HIV-infected patients has been attributed mainly to antiretroviral drugs, in particular protease inhibitors, but specific mechanisms responsible for dyslipidemia have not been fully characterized. Even less is known about changes in lipid metabolism induced by HIV infection itself. In this application we propose a prospective study with HIV-infected patients to characterize changes in metabolism and functionality of High Density Lipoprotein (HDL), the key anti-atherogenic lipoprotein in the blood, associated with HIV-1 infection and anti-retroviral drugs. We will also correlate these changes with the surrogate measures of progression of atherosclerosis in these patients. Studies in vitro will address the mechanism of HIV-mediated effect on HDL The following Specific Aims are proposed: . Specific Aim 1: To characterize effects oLHIV disease on atherosclerosis and metabolic dysregulation. . Specific Aim 2: To characterize the effect of HIV disease on HDL composition and structure. Specific Aim 3: To characterize effects of HIV disease on HDL functionality. Specific Aim 4: To characterize cellular mechanisms responsible for impairment of HDL metabolism. . Research described in this proposal is a mUlti-PI program that will rely on collaborative efforts of clinical cardiologists, basic science cardiovascular researchers and virologists at three sites: the George Washington University, Harvard University and BakerlDI Heart and Diabetes Research Institute.